1. Field of the Invention
The present invention relates to a plasma processing apparatus for performing plasma processing such as plasma etching, a plasma processing method, and a non-transitory computer-readable medium storing a program for executing the plasma processing method.
2. Description of the Related Art
For example, in a process of manufacturing a semiconductor device, plasma processing, e.g., etching or chemical vapor deposition (CVD), is widely performed on a semiconductor wafer which is a substrate to be processed.
Among various plasma processing apparatuses for performing the plasma processing, a capacity coupled parallel plate plasma processing apparatus is mainly used.
When a capacity coupled parallel plate plasma processing apparatus is used as an etching apparatus, there is generally being employed an apparatus that disposes a pair of parallel plate electrodes, i.e., upper and lower electrodes, in a chamber to introduce a process gas into the chamber, forms a high frequency electric field between the parallel plate electrodes to form plasma by applying high frequency to one of the parallel plate electrodes, and applies high frequency for dragging ions to the lower electrode (for example, Patent Reference 1).
However, when an etching process is performed by using this type of plasma processing apparatus, an electrode plate of the upper electrode is consumed due to repetitive plasma processing, and accordingly, a temperature of the electrode plate is increased. If the temperature of the electrode plate is increased, an etching rate varies.
Accordingly, at a point in time when consumption of the electrode plate is beyond an allowable range of an etching rate, the electrode plate is replaced. Although it is not an example of a plasma electrode, as a method of determining time for replacing an electrode, a method disclosed in Patent Reference 2 is used. In the method disclosed in Patent Reference 2, a tracer is embedded in an electrode, and the electrode is replaced when the tracer is detected.
However, in future, if a semiconductor device is further miniaturized, it is expected that an extremely small variation in etching rate is a problem. In particular, it is expected that the extremely small variation in etching rate is a big problem when a degree of consumption of an electrode plate of an upper electrode is serious. However, it is difficult to resolve such a problem, although the above-described technology is used.
3. Prior Art Reference
(Patent Reference 1) Japanese Patent Laid-Open Publication No. 2000-173993
(Patent Reference 2) Japanese Patent Laid-Open Publication No. hei 8-203865